Objectives: Bacterial vaginosis (BV) is common in lesbians, and treatment fails in up to 28%. Risks include sexual behaviours that transmit vaginal fluid. The authors measured efficacy of a behavioural intervention to reduce sexual transfer of vaginal fluid between female sex partners in reducing BV persistence. Methods: Women aged 16-35 years with BV who reported sex with women (prior year) were eligible. Participants were randomised to intervention (motivational interviewing designed to reduce sharing of vaginal fluid on hands or sex toys post-treatment, by provision of condoms, gloves and water-based lubricant) or control (general STI education) arms. All were treated with vaginal metronidazole and underwent computerassisted self-interview to ascertain sexual behaviours, with test-of-cure at 30 days. Results: Of 129 women with BV, 108 (84%) were eligible; 89 (69%) agreed to enrol. 43 were randomised to control and 46 to intervention; 81 (91%) returned for test-of-cure. BV persisted in 12 (27.9%) of 43 women in intervention and 8 (21.1%) of 38 women in control arms (p1/40.6). Digital-vaginal sex was common posttreatment (50% intervention and 68% control); women randomised to the intervention were less likely to report receptive digital-vaginal sex without gloves than control (31% vs 61%; p1/40.01), without reported lower frequency of other sexual practices. Shared vaginal use of sex toys was infrequent. Conclusions: Although the intervention effected a significant increase in glove use during digital-vaginal sex post-BV treatment, this was not associated with reduction in BV persistence. Shared use of vaginal sex toys was infrequent, suggesting that other mechanisms promote BV in lesbians.